The invention relates to a method for gear shifting a dual clutch transmission.
In the DE 19853824 A1 a dual clutch transmission is disclosed comprising a plurality of gear speeds, in the following also simply referred to as “gears”, comprising a first and a second parallel power transmission branch. A first main clutch relates to a first power transmission branch, while a second main clutch relates to a second power transmission branch. Several gear speeds which are also provided adjacent to each other are allocated to one power transmission branch. For avoiding a driving power interruption during the gear shifting between two gears that are both allocated to one and the same power transmission branch the driving power is transmitted during the gear shifting process at least for a short time period via the other power transmission branch.
The DE 103 49 220 relates to a method for gear shifting a dual clutch transmission of a vehicle. During the process of shifting gears from an initial gear into a target gear where both the initial gear and the target gear are allocated to one and the same power transmission path, for avoiding an interruption in the driving power, at least for a short time a support gear is engaged in the respective other power transmission path. Controlling the gear shifting process in the transmission from the initial gear to the target gear is for this purpose performed in that the rotational speed of the motor torque approaches the synchronized rotational speed of the target gear at an almost constant gradient.
The DE 101 51 260 A1 relates to a method for controlling a dual clutch transmission. For achieving a sportive driving performance in case of shifting back two gears on purpose no interruption free power transmission when changing over to the other partial transmission is performed during the downshifting process.
The time needed for gear shifting the dual clutch transmission from an initial gear to a target gear when the target gear and the initial gear are allocated to a joint drive shaft may depend crucially on the time period required for disengaging a gear wheel relating to the initial gear or the time period needed for fixedly connecting a gear wheel that relates to the target gear. Typically, a gear wheel belonging to the target gear can be connected only when the initial gear wheel has already been disengaged. These processes have to be performed inevitably during a gear shifting action from the initial gear to the target gear so that in total the gear shifting process cannot be faster than the time span needed for disengaging the gear wheel relating to the initial gear and for engaging the target gear.